The role of the immune system in central nervous system regeneration (theoretical considerations)

The nervous and immune systems are shown to be interrelated. Steroids inhibit both regeneration and the immune response. Crushing injuries enhance regeneration. A synthesis of these apparently unrelated phenomena is formulated into an immune hypothesis of regeneration. Steroids, in suppressing the immune response, decrease lymphokine production and the subsequent stimulation of nerve cell regeneration. Crushing injuries to nerve fibers cause nerve protein to become antigenic, thereby eliciting the production of "non-toxic" antibodies, which paradoxically protect the nerve fibers from immune attack and cause an augmented lymphokine production and subsequent nerve cell regeneration.